Multiple sheet feeder



y 1953 w. E. MITCHELL v MULTIPLE SHEET FEEDER 5 Sheets-Sheet 1 Filed 25, 1950 INVENTOR. MAX. 07/15 /'7/rcw4 f I mf WZ'TOE/VE'VS July 14, 1953 W. E. MITCHELL MULTIPLE SHEET FEEDER Filed Aug. 25, 1950 I N V EN TOR. MAL/6V7 /7/ 70/954 4 y 1953 w. E. MITCHELL 2,645,479

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, .32 I N VEN TOR. Wu .c Mwfl Mrcwzu L I W Mm y 4, 1953 w. E. MITCHELL 2,645,479

MULTIPLE SHEET FEEDER Filed Aug. 25, 1950 5 Sheets-Sheet 4- y 1953 w. E. MITCHELL 2,645,479

MULTIPLE SHEETFEEDER Filed Aug. 25, 1950 5 Sheets-Sheet 5 INVEN TOR.

M4 4 wME/V/ TC'HEA A BY I Patented July 14, 1953 UNITED STATES PATENT OFFICE MULTIPLE SHEET FEEDER William E. Mitchell, Peoria, 111.

Application August 25, 1950, Serial No. 181,395

.3 Claims. (Cl. 211-21) This invention'relates to sheet feeders for perforators, folders, embossers, and similar ma chines and more particularly to a sheet feeder for feeding two or more sheets in superimposed relationship.

It is among the objects of the invention to provide an improved sheet feeding mechanism for feeding two or more sheets simultaneously and in superimposed relationship to a receiving machine, which can be provided as an attachment for-an existing feeder or integrally incorporated into a new feeder during manufacture, which can be regulated so that the feeder will feed single sheets at spaced apart intervals, a predetermined number of sheets in spaced apart stacks, or con-- tinuously feed the sheets in superimposed relationship to a predetermined depth, which requires no power or vacuum equipment other than that provided for existing sheet feeders, which, when provided as an attachment, can be installed on an existing sheet feeder with no material modification of the feeder construction, which feeds the paper sheets in the desired manner without crumpling or damaging the sheets, which will feed sheets of different sizes, and which is simple and durable in construction, economical to manufacture, positive and effective in operation, and easy to use. e

Other objects and advantages will become apparentfrom aconsideration of the followingdescription and the appended claims in conjunction with the accompanying drawings wherein:

Figure l is a top plan view of a sheet feeder illustrative of the invention;

Figure 2 is a side elevational view of the feeder shown in Figure 1;

Figure 3 is a fragmentary cross sectional view on the line 3-3 of Figure l; 1 I

Figure 4 is a perspective view of the sheet starting mechanism of the feeder;

Figure 5 is a cross sectional View on the line 5-5 of Figure 4;

Figure 6 is a side elevational view of a drive for the mechanism illustrated in Figure 4, portions being broken away and shownin cross section to better illustrate the construction thereof;

Figure 7 is a fragmentary cross sectional view on an enlarged scale taken on the line 1-1 of Figure l and showing a sheet starting vacuum wheel constituting an operative component of the device;

Figure 8 is a cross sectional view on 8-8 of Figure 7;

Figure 9 is a fragmentary top plan view of a the line somewhat modified form of feeder; and a.

Figure 10 is a fragmentary side elevational view of the modified feeder illustrated in Figure 9.

With continued reference to the drawings, the feeder has a main frame including a pair of upright standards it and I l secured together in spaced apart and substantially parallel relationship. These standards have substantially straight edges on their forward sides but have rearwardly projecting extensions at their top and bottom ends.

A vertically disposed guide bar i2 is mounted between the rearward ends of the extensions on.

the column If] and a similar guide bar [3 is mounted between the rearward ends of the extensions on the column H. A flat table I4 is slidably mounted on the guide bars l2 and 13 for vertical movement and the front end of this table slidably engages tracks carried by the standards l0 and H at the front edges of the latter.

The tablesupports stacks of paper Sheets from which the sheets are fed to a receiving machine,

the sheets being fed from the top of the stackssupported on the table. A conveyor is supported by the main frame standards l0 and H at the front edges of the standards and extends away from the front ed of the table l4. This-conveyor is generally indicated at [5 and has a frame including spaced apart and substantially parallel side members l6 and I1. ends in the main frame standards ID and H near the upper front corners of these standards and carries a roller IS. The conveyor frame side members 16- and I! are provided at their ends adjacent the table (4 with apertures which receive the roller shaft l8 to mount the conveyor frame on the main frame of the feeding machine. The side frame members It and I! are also provided with bearing apertures at their other ends and a roller 20 is journaled at its ends in these bearing apertures. Conveyor tapes 2| in the form of endless belts extend around the rollers 19 and 20 in spaced apart and substantially parallel relationship to each other for conveying paper sheets away from a stack of such sheets supported on the table I4;

A chain sprocket is mounted on one end of the roller shaft [8 and a chain 22 connects-this sprocket with a chain sprocket on a power driven receiving machine, such as a perforating or folding machine to drive the conveyor through the shaft I8 and roller I9.

Rods 23 and 24 extend transversel of the conveyor one near each end thereof and are supported above the conveyor by suitable brackets 25 connected at their upper ends to the corre- A roller shaft I8 is journaled at its 3 sponding ends of the rods 23 and 24 and at their lower ends to the conveyor frame side members -l6 and I1.

Bars ZB and 2! are carried by the rods 23 and 24 above and substantially parallel to the conveyor tapes 2| and at respectively opposite sides of the conveyor and each of these bars carries a plurality of spring fingers 28 secured to the bars at spaced apart locations therealon and.

The end of the conveyor remote from the main frame of the feeder is connected to the receivin machine and is supported by the receiving machine at the proper height to feed the sheets of paper into the receiving machine.

A worm shaft 33 is disposed directly above the shaft 3| and journaled at its ends in bear,-

ing brackets supported on the upper surfaces of the standards H3 and H. A ratchet Wheel 34 is secured on the shaft 33 near one end of the latter and a carriage 35 pivotally mounted on the shaft adjacent the ratchet wheel 33 carries a pawl 36 which engages the ratchet wheel.

A gear 37 is secured on the end of shaft l3 adjacent the carriage 35 and an eccentric gear 38 is journaled on the standard |& and meshes with the gear 31. A link rod 39 is connected at one end to the gear 33 eccentrically of the axis of rotation of this gear and is pivotally connected at its other end to the carriage35 to rock the carriage as the gear 38 is rotated by the gear 31 secured on the roller shaft l8.

Rocking of the carriage 35 causes the pawl 33 to impart step by step rotational movement to the ratchet wheel 34 and the shaft 33.

A worm wheel shaft 40 is journaled at its ends in bearing brackets 3| and 32 supported on the upper edge of the standard It and extending thereabove and is disposed substantially perpendicular to the shaft 33. This shaft 40 carries on one end a worm wheel 43 meshing with a worm 44 on the shaft 33 and carries at its other end a chain sprocket 45. An endless chain 46 is carried over the sprocket 45 and connected to the table l4 so that, as step by step rotational movement is imparted to the shaft 43 by the worm and gear connection between the shaft 33 and the shaft 33, the table will be slowly raised A shaft 92 corresponding to the shaft 43 is located above the upper edge of the standard II and is also driven by the shaft 33 through a worm and worm gear connection and a sprocket secured on one end of this shaft 92 carries a chain corresponding to the chain 36 and connected to the edge of the table remote from the chain 46 so that the table is raised by even pulls on the two sides thereof.

The raising of the table and the stack of sheets supported thereon is controlled by a gauging mechanism including a shaft 83 journaled in brackets 83 and 85 projecting inwardly at spaced apart locations from the upper end of the standard l0, an arm Bl connected at one pin. 88 which rests upon thectop sheet,;.of the table carried stack, and an arm 89 which Dro- J'ects from the shaft 83 near the front end of this shaft under the pawl 35 at the side of the pivotal connection between the pawl and the carriage 35 remote from the ratchet Wheel 34.

With this arrangement, when the top of the stack on the table It goes down by the feedin of sheets from the top of this stack, the shaft 83 rotates in a direction to raise the distal end of the arm 89 and this ,moves the pawl 33 to engage the ratchet wheel and rotate the shaft 40 to raise the table.

When the table has been raised to a sufficient height, the shaft 83 is rotated to lower the distal end of the arm 89 and free the pawl for movement by the ratchet wheel to a position in which it does not engage the ratchet wheel upon rocking movements of the carriage 35. The pawl is releasably held in eitherfof the above indicated positions by a ball detent 90 engaging a depending finger 9| on the pawl.

A vacuum wheel shaft 3| is iournaled at its ends in the main frame standards I!) and II above and slightly rearwardly of the roller shaft l8 and a vacuum wheel 32 is mounted on this shaft intermediate the length of the shaft and in position to contact the front portions of the top sheets of stacks of sheets supported on the table l4.

A gear 3'! is secured on shaft l8 adjacent the sprocket carrying the chain 22 and meshes with a gear 48 journaled on the standard II and connected through a speed reducing belt drive 49 to the shaft 3| so that the shaft 3| is continuously driven while the feeder is in operation.

The vacuum wheel 32 comprises a cylindrical body having a coaxial bore therethrough receiving the shaft 3|, the shaft being drivingly connected to the body of the wheel by suitable means, such as the key 53, disposed in complementary keyways in the body and the shaft 3|.

A circular series of closely spaced bores 5| is provided in the body near the peripheralsurface thereof with the bores extending longitudinally of the body and opening to one end thereof, the

bores being closed at the other end of the body, as indicated at 52. Series ofapertures 53 equal in number to the number of bores 5| are provided in the body extending from the peripheral surface of the body to the corresponding bores. The apertures in each series are spaced apart longitudinally of the body and, when one of the bores 5| is subjected to vacuum, the corresponding apertures 53 are also subjected to vacuum to momentarily pull a sheet of paper against the peripheral surface of the wheel or roller 32.

An arm 54 is provided with two spaced apart apertures one of which receives the shaft 33 and the other of which receives the shaft 3|. The arm 54 has an enlarged portion 55 surrounding the shaft 3| and extending to the surface of the wheel or roller 32 at the sideof shaft 3| remote from shaft 33. A passage 56 is provided in this arm and a port 57 extends from the passage 56 to the surface of the arm adjacent the corresponding end of the wheel 32 at a location in alignment with the axes of the two shafts 3| and 33 toconnect the passage with that port 5| in the wheel at the lowest portion of the wheel and directly above the portion of the wheel in contact with the top sheet of paper on the stack carried by the table l4, so that the vacuum exerted through the corresponding apertures 53 will pull. the sheet of paper against the lower surface ofthe wheel. Surrounding the port 51 the arm has aformation which closely contacts the adjacent end surface of the vacuum Wheel to provide a substantially leakproof connection between the arm and the wheel surrounding the port and, as the port 51 has an arm no larger than the cross sectional area of the bores 5|, only one bore will be subjected to vacuum at a time.

A vacuum pump 58 is provided adjacent the feeding machine and is connected through suitable conduits, such as the flexible hose 5Q, T joint so, automatic valve assembly 6|, pipe 62, T and elbow joint assembly63 and flexible hose 64 to the arm 5 3-, the end of the hose 64 remote from the pipe fitting assembly 63 being fitted onto a tubular extension 65 provided on the arm 54 and communicating with the passage 56-.

A shaft 63 extends transversely of and below the conveyor [5 intermediate the length of the conveyor and is journaled at its'en'ds in brackets 61 and 68 secured to and depending from the conveyor frame side members It and [1 respectively. A chain sprocket is mounted on one end of this shaft E6 and is connected by a chain 69 to a power driven chain sprocket on the receivin machine to which the feeder is connected. A cam "it is secured on the other end of the shaft at the outer side of the bracket 61 and a lever H is pivotally connected at one end to the bracket 67 and bears intermediate its length against the cam iii. A link rod 12 connects the free end of the lever H to the vacuum valve 6| so that this valve will be operated in timed sequence to the operation of the receiving machine, such as the folder or perforator, connected to the feeder. By this periodic operation of the vacuum valve 6|, sheets will be picked off the top of the stack carried by the table it by the vacuum Wheel 32 at spaced apart intervals and will be fed in properly timed sequence to the receiving machine.

The valve BI is provided in its side adjacent the vacuum pump 63 with an opening and a bell crank 13 is pivotally mounted on the valve and has one end provided with a pad which covers and closes this opening in one position of the bell crank. A pull rod M is'connected at one end to the other end of the bell crank and extends through an aperture in the pin 15 by which the lever ll is mounted on the bracket 61 and carries a pull knob 76 on its end remote from the bell crank E3. By manually pulling on the knob ":6 the opening in the valve 6| can be un covered to discontinue the application of vacuum to the vacuum wheel. Thus, feeding of sheets by the vacuum wheel can be manually interrupted by the operator of the machine whenever necessary or desirable.

The valve body Ti and the valve plunger 18 are provided with transverse apertures which register when the valve is open and a pin 19 is provided which can be inserted through these apertures when in alignment to hold the valve open and thereby render the cam 10 ineffective to operate the automatic valve 6|. Under these conditions, vacuum will be continuously applied to the vacuum wheel so that the sheets will be fed from the top of the stack in close sequence with no substantial intervals therebetween.

A manually adjustable valve 80 is connected into the T fitting 60 between the valve 6! and the vacuum pump 58 and an air filter 8| is connected to the side of the valve 8!] remote from the T fitting 60. The valve 80 can be manually adjusted to control the extent of vacuum applied to the vacuum wheel by the vacuum pump.

Arms, as indicated at 82, are connected to the 6 frame side members [6 and I1 near the end of the conveyor l5 remote from the main frame of the feeder for connecting this outer end of the conveyor to the receiving machine.

Air nozzles 93 are supported by a suitable bracket structure 94 from the standards l8 and H and are positioned adjacent the upper edge of the front end of the stack of sheets 95 supported on the-table M to maintain the top sheets of the stack in a loose condition so that the top sheet can be easily moved from the top of the stack by the vacuum wheel- 32 A support bar 95 extends transversely of the table above and intermediate the length of the latter and is supported at its ends on the standards l0 and I l. Spaced apart guide rods 96 and 91- are secured at their rear ends to this support rod- 95 and extend forwardly over the conveyor id to hold the sheets of paper on the conveyor down on the conveyor tapes 2| and against rolling or lifting and stack guides 98 and 99- are also mounted on the support bar 95 at the outer sides of the guide rods 96 and 9?- res-p'ectively and carry pins which extend downwardly at the respectively opposite sides of the table supported stack to maintain the stack in proper position on the table and the side edges of the stack substantially straight as the sheets are from the top of the stack.

As the mechanism above described is well known to the art, a more detailed illustration and description is considered unnecessary for the purposes of the present disclosure.

fhe above described mechanism has a single vacuum wheel or roller permanently located near the front edge of a sheet stack supported on the feeder table and its operation is limited to the feeding of sheets one at a time and at spaced apart intervals along the conveyor to the receivingmachine; The only adjustment available to this machine is to vary the spacing between successive sheets by changing the cam 10.

In many operations, such as perforating and folding, and embossing, it is highly desirable to feed the sheets to the receiving machine, such as the folder, perforator or embosser in successive, spaced apart stacks with each stack containing a predetermined number of sheets. A perforating machine, for example, is fully capable of perforating a number of sheets at the same time and, unless the sheets are fed to it in this manner, the capacity of the perforating machine is greatly reduced. The present invention provides means for feeding the sheets to the receiving machine in spaced apart, successive stacks, each of which contains a predetermined number of sheets or for continuously feeding the sheets in superimposed and overlapping relationship, as may be desired.

In accordance with the present invention, a pair of bearing brackets I00 and [Ill are mounted on the shaft 3| at the outer sides of the stack guides 98 and 99 respectively. These bracketsare provided with bearings I02 and I03 in which the continuously rotating shaft 31 is journaled and two rails i0 1 and I95 are rigidly connected at their front ends one to each of the brackets 10!] and GUI above the shaft 3|. These rails extend rearwardly from the shaft 3| in spaced apart and substantially parallel relationship to each other and two guideway brackets I06 and I01 are slidably mounted one on each of the rails I04 and H15 rearwardly of the shaft 3!.

The rails H04 and I05 are of elongated rectangular cross sectional shape and each of the brackets I and IE1 may conveniently be formed of a plurality of rectangular plates secured together to provide between mutually opposed plates rectangular guideways I38 and IE9 in which the rails I04 and I05 are slidably received.

The bracket I is provided with two spaced apart apertures III) and III disposed one above and one below the corresponding rail I04 and the bracket I01 is provided with two corresponding, spaced apart apertures H2 and H3.

A shaft I14 extends at its ends through the apertures in brackets I05 and I01 disposed below the corresponding rails I04 and I05 and the brackets are provided respectively with bearings H5 and IIG in which the shaft H4 is journaled near the opposite ends of the shaft.

A support bar I I? has its opposite ends secured in the apertures H3 and H2 disposed above the rails I32 and I35 so that this support bar is disposed above the shaft III4 and substantially parallel to the shaft.

A vacuum wheel H8 is mounted on the shaft I I4 intermediate the length of this shaft and an arm H9 is disposed against one of the vacuum wheel H8 and provided with spaced apart apertures respectively receiving the shaft I I4 and the supporting bar H1.

The vacuum wheel I18 and thearm III! are of the same construction as the vacuum wheel 32 and arm 52 described above and illustrated in 7 detail in Figures 7 and 8.

A pipe fitting assembly I23, similar to the assembly 53, is connected to the upper end of the vacuum pipe 52 and a flexible hose I2I extends from the fitting assembly I23 to the arm H9 to apply vacuum to the vacuum wheel H8. The hose 54 and the hose I2I are both connected to the vacuum pump through the common vacuum pipe 62, valve TI and hose connection 59 so that both of the vacuum wheels 32 and H8 are subjected to vacuum in the same manner and the vacuum applied to both of these vacuum wheels is controlled by the valve 'II operated in the manner described above.

An adjustable drive is provided between the shaft 3| and the shaft M5 for driving the rear vacuum wheel H8.

This drive connection may conveniently comprise two gear housings I25 and I25, a splined or longitudinally grooved shaft I27 and two beveled gear trains mounted one in each of the housings.

The housing I25 is a U-shaped structure of rec- I tangular shape having a bight portion and a pair of spaced apart and substantially parallel legs provided near their ends remote from the bight portion with registering apertures which receive the shaft 3i. The bight portion of this bracket is provided with an aperture receiving a bearing I28. A beveled gear I29 is mounted on the shaft 3| between the legs of the housing I25 and a beveled gear I33 meshes with the gear I29 and has a cylindrical hub I3I mounted in the bearing I28. The longitudinally grooved shaft or spline shaft I2? has one end secured inthe hollow hub I3l of the gear I38 and secured in this hub by suitable means, such as the through'pin I32. I

The housing I25 has in its bight portion an aperture receiving the shaft H4 and a beveled gear I33 is disposed'between the two legs of the housing I26 and mounted on the corresponding end of the shaft IN.

The bracket I25 is disposed substantially at right angles to the bracket I25 so that one leg 3 of the bracket I26 is substantially parallel to the bight portion of the bracket I25. This one leg of the bracket I28 is provided with an aperture receiving a bearing I35 and a beveled gear I35 meshes with the gear I33 and has a hollow cylindrical hub I36 received in the bearing I34. The splined shaft I2? extends through the gear I35 and its hub and through an aperture provided in the other leg of the housing I26, the housing I26 and gear I35 being slidable along the shaft With this arrangement, the assembly including the shafts III and III, the slideway brackets I35 and IE1, the vacuum wheel H8 and the arm He can be moved along the rails Ifi l and I35 toward andaway from the front vacuum wheel 32. As the above described assembly is moved longitudinally of the rails I34 and I35, the housing I26 and the gear I35 will be simultaneously moved along the shaft I2? to maintain the driving connection between the shafts 3| and H4.

If the shaft I2? is provided with a single longitudinally extending groove, as illustrated in Figure 6, it may be drivingly connected to the gear I35 by a suitable key I3! received in the groove I33 of the shaft I2? and in a complementary keyway provided in the hollow hub I36 of the gear I35.

Blocks I43 and IIII are secured on the outer sides of the rails I34 and I35 respectively adjacent the brackets IIIII and IGI and each of these blocks is provided with a. screw threaded bore extending therethrough from its u per to its lower side. A screw threaded rod I42 is threaded through the bore in the block M3 and a similar rod I43 is threaded through the bore in the block IIII. An inverted U-shaped saddle I43 is pivotally mounted on the lower end of the rod I32 and a similar saddle I35 is pivotally mounted on the lower end of the shaft M3. The saddles Hi l and I45 rest upon the support bar and support the rails I34 and I05 above this support bar so that the rails will support the rear vacuum wheel assembly above a stack of paper sheets carried on the table I l. The elevation of the rear vacuum wheel IIB relative to the top sheet of the stack can be adjusted by turning the screw shafts I42 and I43 by suitable means, such as the through pins, as indicated at I45, extending through the upper ends of the screw shafts and the rear vacuum wheel assembly can be locked in adjusted position by suitable lock nuts VII and I48 threaded on the screw shafts I42 and I43 respectively and bearing against the corresponding blocks I43 and MI.

A rectangular plate I53 is disposed in position to rest upon the top of the stack 95 carried by the table III and is supported in this position by a pair of hangers I5I and I52 journaled at their upper ends on the shaft 3| and depending from this shaft to the plate with their lower ends rigidly secured to the plate and by a pair of hangers I53 and I53 journaled on the shaft Ill and having slides on their lower ends slidably received in slots I55 and I55 extending longitudinally of the plate I5I) near the respectively opposite sides of the plate.

The plate is provided near its front end with a rectangular aperture I57 through which the front vacuum wheel 32 projects to contact the top sheet of paper on the stack 95 and with an elongated slot I58 which extends from a location adjacent the aperture I5I to the rear end of the plate and receives the rear vacuum wheel H8. This plate maintains the top sheet on the stack 9 in a straight and flat condition so that it will not roll or wrinkle when subjected to a pull by the vacuum wheels. I

- Operation Assuming first, that it is desired to feed two sheets at a time from the stack 95 to the re-, ceiving machine, the rear vacuum wheel .I I8 will be set near the rear end of the stack. Now, as the feeder operates, both vacuum wheels will engage the top sheet on the stack and urge this sheet forwardly. Assoon as the rear edge of this top sheet passes the rear vacuum wheel I8 the rear vacuum wheel will engage the next sheet and urge this sheet forwardly along with the top sheet. The position of the rear vacuum wheel and the shape of the cam '50 is such that just before the rear edge of this second sheet passes the rear vacuum wheel, the vacuum to the vacuum wheels-will be cut ofi so that the rear vacuum wheel Will not pick up the third sheet.- The first and second sheets will, however, reach the forwarding rollers I9 and 30 before the second sheet passes entirely from under the rear vacuum wheel H8. As soon as the two sheets under consideration have been moved a predetermined distance along the conveyor toward the receiving machine, the cam I will again open the vacuum controlling valve I1 to apply vacuum to the vacuum wheels 32 and IE8 and two more sheets will be picked up and forwarded along the conveyor.

As diagrammatically shown in Figure 2, the receiving machine is provided with a pair of vertically disposed and mutually opposed feed rollers I00 and I BI and a gate I62 disposed-behind the top feed roller I60. Theoperation of this mechanism is such that the top feed roller I60 is momentarilyraised and the gate I62 simultaneously lowered to stop the feeding of sheets to the receiving machine. During this interval the two sheets passing along the conveyor are moved between the rollers I60 and NH so that their forward edges engage the gate I62. The gate stops the top sheet but the continuing operation of the conveyor moves the bottom sheet up until its front edge, also contactsthe gate. the top sheet being thus Iexactly superimposed on the bottom sheet. The mechanism of the receiving machine then lifts the gate I62 and simultaneously lowers the top feed rooler I60 into engagem ent with the top sheet and the two sheets are then fed together into the receivin machine. The feeder will thus feed spaced apart stacks each including two superposed sheets to the receiving machine in timedsequence to the opera-.

tion of thereceiving machine, as the cam ID is driven by the receiving machine in timed relationship to the operation of the feed roller I60 and gate I62.

A third sheet may be added to each stack by merely moving the rear vacuum wheel H3 and its supporting assembly further to the rear of the stack so that the distance between a vertical plane extending through the axis of the rear vacuum wheel and the rear end of the stack is substantially equal to the peripheral travel of the rear vacuum wheel during the time the valve 11 is held open by the cam l0. If it is desired to add additional sheets to each stack moving along the conveyor this can be done by changing the gear ratio of the drive from the shaft 3i to the shaft Il'l in a manner to speed up the rotation of the rear vacuum wheel H8.

Under certain operating conditions, as where sheets without insets or strike-ins are being continuously perforated by aperforating machine, a continuous feed of such sheets to the perforator can be provided by locking the vacuum valve 1! in open position by the pin I9; Under these operating conditions, as the rear edge of the top sheet passes the rear vacuum wheel, this vacuum wheel will immediately start the next succeeding sheet in a forward direction so that the sheets will be fed in a mutually superimposed and overlapping relationship along the conveyor and into v ment being illustrated in Figures 9 and 10.

In this modified arrangement, a Supporting rod or bar I65 is substituted for the front vacuum wheel shaft 3| and is positioned forwardly of the position of the front vacuum wheel shaft, beinglocated substantially above the rear conveyor roller I9.

The front brackets I00 and IM mounting the. front ends of the rails I04 and I05 respectively are pivotally mounted on this bar I65 and extend rearwardly substantially to the rear end of the table I4. The slot I58 in the plate I50 is extended forwardly to include the aperture I5"! for the front roller and two stub shafts IE5 and I5? are mounted on the main frame of the feeder one at each side of the table with their adjacent ends spaced apart so that the rear roller assembly can pass between these stub shafts from a position near the rear end of the table to the position occupied by the non-adjustable front roller in the known form of the machine illustrated in Figures 1 and 2 and described above.

In this case the pipe fitting assembly 63 and the flexible hose 64 is also omitted and the blocks I40 and MI are moved forwardly of the corresponding rails I04 and I05 so that the saddles I44 and I 45 engage the inner ends of the stub shafts I66 and I6! respectively so that these blocks do not interfere with forward movement of the brackets I06 and I0! to a position corresponding to the position ofthe vacuum wheel in the existing machine. With this somewhat modified form of the invention, by setting the single vacuum wheel I I8 at the position of the vacuum wheel 32 in the. above described arrangement, a single sheet feeding operation is provided in which single sheets ar fed successively along the conveyor at intervals controlled by the cam 10. By moving the vacuum wheel in the modified arrangement rearwardly, the sheets can be forwarded in successive stacks each including two or more sheets and the number of sheets in each stack can be increased by increasing the speed of the vacuum wheel relative to the operation of the cam I0. .Also, by locking the vacuum valve open and placing the vacuum wheel near the rear end of the table supported stack, the sheets can be continuously fed in mutually superimposed and overlapping relationship.

If the sheets to be fed are too long to be conveniently handled by a single vacuum wheel spaced from the forward ends of the sheets, the vacuum wheel can be moved to a position near the forward ends of the sheets and a second assembly added to provide a second vacuum wheel spaced rearwardly of the forward ends of the sheets.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

What is claimed is 1. In a sheet feeding machine having a main frame, a vertically movable table carried by said main frame for supporting a stack ofjsheets from which sheets are successively fed, 'a conveyor carried by said main frame at one end of said table and in position to receive sheets fed from a stack supported by said table, a power driven shaft supported by said main frame above said one end of the table, a vacuum wheel mounted'on said shaft in position to engage the uppermost sheet of a table supported stack, a vacuum pump, means including avacuum controlling valve connecting said vacuum pump to said vacuum wheel, and a power driven cam operating said valve to apply vacuum to said vacuum wheel at successive intervals of a duration to provide a predetermined spacing between successive single sheets moved by said vacuum wheel from a table supported stack to said conveyor, multiple sheet feeding means for the sheet feeding machine comprising a second power driven shaft substantially parallel to the first mentioned shaft and spaced from the latter toward the other end of said table, a second vacuum wheel mounted onsaid second shaft in position to engage at the location of said second vacuum wheel the uppermost sheets on a table supported stack, means connecting said second vacuum wheel to said means connecting the first mentioned vacuum wheel to said vacuum pump, means drivingly interconnecting said first and second shafts for rotation in the same direction and at substantially the same speed, and means supporting said second shaft for movements of adjustment toward and away from the first mentioned shaft.

2. In a sheet feeding machine having a main frame, a vertically movable table carried by said main frame for supporting a stack'of sheets from which sheets are successively fed, a conveyor carried by said main frame at one end of said table and in position to receive sheets fed from a stack supported by said table, a power driven shaft supported by said main frame above said one end of the table, a vacuum whee1 mounted on said shaft in position to engage the uppermost sheet of a table supported stack, a vacuum pump, means including a vacuum controlling valve connecting said vacuum pump to said vacuum wheel, and a power driven cam operating said valve to apply vacuum to said vacuum wheel at successive intervals of a duration to provide a predetermined spacing between successive single sheets moved by saidvacuum wheel from a table supported stack to said conveyor, multiple sheet feeding means for the sheet feeding machine comprising a second power driven shaft substantially parallel to the first mentioned shaft and spaced from the latter toward the other end of said table, a second vacuum wheel mounted. on said second shaft in position to engage at the location of said second vacuum wheel the uppermost sheets on a table supported stack, means connecting said second vacuum wheel to said means connecting the first mentioned vacuum wheel to said vacuum pump, means drivingly interconnecting said first and second shafts for rotating in the same direction and at substantially th same speed means supporting said second shaft for movements of adjustment toward and away from the first mentioned shaft, and a plate supported by said main frame in superimposed relationship to a stack of sheets supported. on said table and having a longitudinally extending slot therein receiving said second vacuum wheel in the various positions of adjustment of said second shaft relative to said first mentioned shaft.

3. In a sheet feeding machine having a main I frame, a vertically movable table carried by said main frame for supporting a stack of sheets from which sheets are successively fed, a conveyor carried by said main frame atone end of said table 7 and in position to receive sheets fed from a stack supported by said table, a power driven shaft supported by said main frame above said one end of the table, a vacuum wheel mounted on said shaft in position to engage the uppermost sheet of a table supported stack, a vacuum pump, means including a vacuum controlling valve connecting said vacuum pump to said vacuum wheel,'and a power driven cam operating said valve to apply vacuum to said vacuum wheel at successive intervals of a duration to provide a predetermined spacing between successive single sheets moved by said vacuum wheel from a table supported stack to said conveyor, multiple sheet feedingmeans for the sheet feeding machine comprising a second' power driven shaft substantially parallel to the first mentioned shaft and spaced from the latter toward the other end of said table, a second vacuum wheel mounted on said second shaft in position to engage atthe location of said second vacuum wheel the uppermost sheets on a table supported stack, means connecting said second vacuum Wheel to said means connecting the first mentioned vacuum wheel to said vacuum pump, means drivingly interconnecting said first and second shafts for rotation in the same direction,

means supporting said second shaft for move-' mentioned shaft, a pair of rails each secured at one end to the corresponding bracket, a pair of slide brackets slidably mounted one on each of said rails, a support bar extending between and secured at its ends to said slide brackets holding said rails in spaced apart and substantially parallel relationship to each other, bearings carried one by each of said side brackets and receiving said second shaft, blocks secured one on each of said rails and each having a screw threaded aperture therethrough, and through shafts threaded one through each of said blocks for adjustably raising or lowering said second shaft and said second vacuum wheel.

WILLIAM E. MITCHELL.

References Cited in the file of this patent UNITED STATES PATENTS Number 

